Airbag control unit with part number 89170-53390

What does the airbag control unit 89170-53390 do?

The airbag control unit 89170-53390 is the central control unit of the restraint system (SRS) of Lexus. It processes the messages from the crash sensors, decides in an accident which airbags and seatbelt pretensioners are triggered, and checks the system continuously. Faults appear via the airbag warning light; after an accident the unit stores crash data and locks itself.

The decision on triggering is made within milliseconds, so the unit is designed for short reaction times.

Outside an accident, monitoring runs in the background. The unit detects interruptions and faults in the circuit of the restraint system and records them in the fault memory.

Why does the control unit 89170-53390 fail?

The most common cause is crash data stored after an accident, even if no airbag has deployed; a normal diagnostic tool cannot erase this data. Other possible causes are aged electronics, cold solder joints, moisture and corrosion on connectors, and voltage spikes.

Crash data is where fault-finding can begin. It remains in the unit even if no airbag was triggered.

The other causes tend to be gradual. Aged components and cold solder joints show up over time, while moisture and corrosion attack the contacts on the connectors.

Voltage spikes arise, for example, from a weak battery or a jump start and can strain the electronics.

How can you tell that the 89170-53390 is defective?

The airbag warning light in the instrument cluster stays on constantly or only intermittently, an error message appears in the instrument cluster, the diagnostic tool cannot reach the control unit, or the fault memory cannot be cleared. In an emergency, airbags and seatbelt pretensioners may then fail to deploy.

The warning light is the first and most important sign of a fault in the restraint system. When it lights up, take it seriously and have the system checked.

A light that comes on only intermittently also counts as one of these signs. If the fault memory cannot be emptied despite an attempt to erase it, a cause is likely that needs checking.

Which vehicles is the 89170-53390 fitted in?

The airbag control unit 89170-53390 is fitted in these vehicles: Lexus IS XE30 Facelift (2016-2020) and XE30 (2013-2016). The list states the vehicles known so far to have this control unit.

The vehicles known to have this control unit are listed in this overview:

• Lexus IS XE30 Facelift (2016-2020)
• Lexus IS XE30 (2013-2016)

Before sending it in, compare the part number on the label of the removed unit with this page. That only confirms that it is the correct unit. First have the fault memory read out, because only this result shows whether the control unit is defective or whether a connector or cable is the cause.

For the same vehicles, we also repair control units with the part numbers 89170-53250, 89170-53370, 89170-53700.

How does the repair of the 89170-53390 work?

First have the fault memory read out and attach the log. Then disconnect the battery, remove the control unit and create a repair order online. Airbag24 checks the unit, replaces defective components, erases stored crash data and carries out a function test before your own unit is returned.

The sequence is mandatory for safety reasons, because the unit may only be removed after the battery has been disconnected.

Processing at Airbag24 usually takes 3–4 working days. This time covers only the checking, repairing and testing.

Our repairs come with 2 years' statutory liability for defects. The repaired control unit comes back with all vehicle data and is ready for use as soon as it is refitted — no coding or programming is required.

How does the control unit 89170-53390 get to Airbag24?

You send the unit in as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns the unit by UPS.

Put the printed repair order into the parcel and pack the unit shock-proof.